[time-nuts] GPSD-Rb

[Peter Bell]

On Wed, Aug 22, 2012 at 11:27 PM, Chris Albertson <albertson.chris at gmail.com
> wrote:

>
> It is very hard to write a divers in software.  You have to use assembly
> language and you have to mmake sure that EVERY path in every branch is has
> exactly the same number of clock cycles.   And then you have to be lucky
> that you can work out an exact integer division.
>

It depends on what sort of processor you are using - that sort of approach
used to be
necessary when the low-cost MCUs were things like PICs that don't have
especially sophisticated on-chip timers, but even cheap devices now have
onchip
timer/counters that have reload and capture registers. Many of them also
have PLLs
on the die that are intended for clock generation but can often be abused
for other
purposes :)